Building element and associated reinforcing device

ABSTRACT

A building element for a building includes a framework with at least one wooden beam and at least one facing sheet fixed to the beam of the framework. The building element also includes an insulating component made of mineral wool affixed to the beam in such a way as to cover the beam on the one hand on a frontal face and on the other hand on at least a part of the lateral faces. The insulating component affixed to the frontal face is interposed between the facing sheet and the beam.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a building element intended in particular for constructing a building, such as a house, a property, etc. and to an associated reinforcing device.

TECHNOLOGICAL BACKGROUND

Building using wooden elements is nowadays becoming increasingly widespread by users anxious to limit their impact on the environment.

In general, such a building element comprises a wooden framework with several beams or members assembled to form the leadbearing structure of the element and one or more facing sheets, for example made of plasterboard or particle board, fixed to the framework. An insulating layer, for example of mineral wool, is positioned between the beams of the framework in order to provide the building element with thermal and acoustic insulation.

From a standpoint of leadbearing capacity, energy comfort and soundproofing, these building elements are entirely satisfactory, both in their use in the building of walls or partition walls and in their use for constructing floors or ceilings.

However, the fire resistance of such building elements remains a constant preoccupation.

Specifically, when exposed to fire, the performance in terms of mechanical integrity, in particular the loadbearing capacity of the wooden framework, is reduced in particular as a result of the charring of the wood fibers which may lead to the structure collapsing, even if the plasterboard and the mineral wool of the building element provide the framework with some degree of protection and delay this failure.

The applicant company has conducted experiments in order to evaluate the fire resistance of such building elements. Thus, a building element formed of wooden beams 45 mm×145 mm in cross section from class C30 and a sheet of fire-resistant plasterboard of type F, 20 mm thick, had a resistance time of around 78 min.

Increasing this time is of key importance for example for lengthening the time available to evacuate the occupants from the building in the event of fire. This becomes all the more important in the context of a multi-storey building constructed using such building elements.

Furthermore, building elements are subject to fire resistance standards. In particular, standard EN1363/1364 defines an R.E.I. class followed by a numeral. In summary, this R.E.I. class followed by a numeral expresses, in minutes, the length of time for which a building element simultaneously meets the following criteria:

-   -   Loadbearing capacity: the time for which the element maintains         its loadbearing function (in the case of elements having a         loadbearing function).     -   Integrity: the time for which no smoke or flames pass onto the         non-exposed side of the wall (in the case of elements having a         dividing function).     -   Insulation: the time for which the temperature on the         non-exposed side does not increase above a certain temperature         threshold.

Increasing the fire resistance additionally allows a better classification against the standards and therefore opens the way for the building element to have a broader field of application in the erection of buildings.

OBJECTIVES OF THE INVENTION

The present invention seeks to propose a building element having improved fire resistance.

According to another independent objective, the invention seeks to propose a device for reinforcing such a building element.

SUMMARY OF THE INVENTION

Thus, one subject of the invention is a building element for a building comprising a framework with at least one wooden beam and at least one facing sheet fixed to the beam of the framework, characterized in that it comprises an insulating component made of mineral wool affixed to the beam in such a way as to cover said beam on the one hand on a frontal face and on the other hand on at least a part of the lateral faces, the insulating component affixed to the frontal face being interposed between the facing sheet and the beam.

The building element may further comprise one or more of the following features considered alone or in combination:

According to one aspect, the insulating component made of mineral wool covers the lateral faces completely.

According to another aspect, the insulating component made of mineral wool is also affixed to the rear face of the beam that is the opposite face to the frontal face, so that it completely surrounds said beam.

On each face to which the insulating component is affixed, the orientation of the fibers comprises a component parallel to this face, in particular the dominant direction of the orientation of the mineral fibers of the insulating component made of mineral wool is parallel to this face.

The thickness of the insulating component is, for example, greater than or equal to 15 mm and in particular comprised between 15 mm and 50 mm and is more particularly 25 mm.

The density of the insulating component made of mineral wool is, for example, greater than or equal to 30 kg/m³, in particular comprised between 80 kg/m³ and 100 kg/m³ and more particularly comprised between 85 kg/m³ and 91 kg/m³.

Provision may be made for the mineral wool of the insulating component to be made with high-temperature-resistance mineral wool fibers.

The insulating component may be affixed to the wooden beam by bonding and/or mechanical fastening.

The building element may further comprise a reinforcing device having at least one part of U-shaped overall cross section, the bottom of the U being positioned facing the frontal face and the lateral legs of the U facing the lateral faces, each lateral leg being fixed at an end zone in the lateral face of the beam, the insulating component being interposed either between the reinforcing device on the one hand and the beam on the other, or between the bottom of the U and the facing sheet.

According to one aspect, the length of each lateral leg of the reinforcing device is greater than half the thickness of the beam.

The reinforcing device may comprise degassing openings.

The invention also relates to a reinforcing device for a building element as defined hereinabove, characterized in that it comprises, on the one hand, a frontal face intended to be fixed facing the frontal face of a beam and, on the other hand, at least two lateral legs intended to be fixed to the lateral sides of a wooden beam.

According to one aspect, the length of each lateral leg of the reinforcing device is greater than 40 mm, in particular comprised between 50 mm and 70 mm, and in particular, 60 mm.

According to another aspect, the reinforcing device comprises degassing openings.

The invention additionally relates to an assembly of reinforcing devices, characterized in that it comprises at least one pair of reinforcing devices as defined hereinabove, the respective lateral legs of which have complementary cutout shapes.

The invention finally relates to a protection kit for creating a building element as defined hereinabove, characterized in that it comprises at least one mineral wool panel and means of reinforcing the panel on the frontal and lateral faces of a wooden beam, in particular a device as defined hereinabove.

According to one aspect, the kit comprises a panel formed of three continuous or contiguous and in particular chamfered segments connected by their external faces, it being possible for the panel to be folded along pliable hinges so that it surrounds the wooden beam.

The invention will be better understood and further details, features and advantages of the invention will become apparent from reading the following description given by way of nonlimiting example with reference to the attached drawings in which:

FIG. 1 is a schematic perspective view of a building element according to one embodiment,

FIG. 2 is a view in cross section of a detail of a building element according to a first embodiment,

FIG. 3 is a schematic perspective view of a reinforcing device according to a first embodiment,

FIG. 4 is a schematic perspective view of a reinforcing device according to a second embodiment,

FIG. 5 is a schematic plan view of a strip of sheet metal with cutting and folding lines for the manufacture of a reinforcing device,

FIG. 6 shows a view in cross section of a detail of a building element according to a second embodiment,

FIG. 7 shows a perspective view of a wooden beam fitted with two reinforcing devices of complementary shapes,

FIG. 8 is a view in cross section of one exemplary embodiment of an insulating component for a building element according to the invention, and

FIG. 9 is a view in cross section of the exemplary embodiment of an insulating component according to FIG. 8, in the unfolded state.

In all the figures, elements that are identical bear the same reference numerals.

One example of an embodiment will now be described with reference to the figures.

The following embodiments are examples. Although the description refers to one or more embodiments, that does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to one single embodiment. Simple features of various embodiments may also be combined to make other embodiments.

FIG. 1 schematically depicts a building element 1 for a building. By way of example and non-exhaustively, this may be an element that forms a wall, a partition wall, a floor or a ceiling.

It may be a prefabricated element, which means to say an element assembled for example in a factory to be delivered to a building site, or be assembled on site.

The building element 1 may also integrate or incorporate other elements such as, for example, windows or doors, without departing from the scope of the present invention.

The building element 1 in particular comprises a framework with at least one, and in this case three, wooden beams 3 which are for example uniformly spaced apart. These are three leadbearing beams 3. These beams 3 are loadbearing for the building element 1 itself, but may additionally be loadbearing in a broader sense for the building for which it is used. The beam or beams may be of square or rectangular cross section.

Of course, this framework may also additionally comprise wooden crossmembers to stiffen the construction.

At least one sheet of facing 4 is fixed to the beams 3 of the wooden framework. In this embodiment, a single sheet 4 covers the three beams. As an alternative, several sheets, covering only two successive beams, may be juxtaposed laterally.

In addition, a thermally insulating layer 5, for example made of mineral wool such as glass wool or rock wool, is positioned between the beams 3. The insulating layer 5 is, for example, a mineral wool marketed by the applicant company under the trade name “ULTIMATE™”. This is a mineral wool manufactured to a specific method and composition that give it good fire resistance approaching 700° C. This product, available in relatively low density ranges for given thermal performances is an advantage in creating a lightweight building element. For example, use is being made here of a density of 20 kg/m³. A rock wool or glass wool is also conceivable.

FIG. 2 shows, in cross section on line of section II-II, a detail of the building element 1 of FIG. 1, without the insulating layer 5.

As can be seen from this FIG. 2, the building element 1 comprises an additional insulating component 7 made of mineral wool that is different than the insulating layer 5. This insulating component 7 is affixed to the wooden beam 3 and is interposed between the facing sheet 4 and a frontal face 9 of the beam 3 that faces the facing sheet 4. The insulating component 7 is fixed against the beam 3 and extends along lateral faces 11 of the beam 3, so as to cover these partially or completely, typically over at least 50%, and in this particular instance completely. It is in planar contact with the face or faces of the beam.

The insulating component 7 made of mineral wool is formed at least in part of fibers in a proportion of between 80% and 99% by weight.

In addition, the spatial orientation of the fibers comprises a component parallel to the face 9 or 11 to which the insulating component 7 is fixed. For preference, the dominant direction of orientation of the mineral fibers of the insulating component 7 is parallel to the face 9 or 11 to which the insulating component 7 is fixed. This effectively prevents flames from being able to lick the wood of the beam 3 directly when the building element 1 is directly exposed to fire.

The insulating component may thus have a mineral wool felt structure in which the fibers are distributed substantially in the form of layers substantially parallel to the main surfaces of the component. It may also have a structure of felt densified by pendular cross-lapping or by crimping, these two techniques known per se in the field of mineral wool have the effect of partially reorienting the mineral wool fibers with a vertical component in the direction of the thickness of the component. Such a partial reorganization maintains enough of a horizontal orientation to oppose the passage of air, thermal radiation, or flames.

Conversely, a structure of lamellar type, in which the fibers are oriented in layers essentially parallel to the direction of the thickness of the component is not recommended because this creates a chimney effect, offering very little resistance to the passage of air in the direction of the thickness of the component but rather channeling the penetration of smoke or flames into contact with the wooden element that is to be protected.

The insulating component 7 may be made up of continuous or contiguous mineral wool segments.

This insulating component 7 is, in this embodiment, in direct contact with the beam 3 and attached to this beam by bonding using a silicate adhesive or an inorganic mortar and/or mechanical fastening such as, for example, a reinforcing device 13 depicted in FIG. 2.

The insulating component 7 has a thickness that may vary according to the fire protection to be afforded to the wooden element. It is greater than or equal to 15 mm and in particular comprised between 15 mm and 50 mm (end-points included), and is more particularly 25 mm.

The density of the material of the insulating component is, for example, greater than or equal to 30 kg/m³, in particular comprised between 80 kg/m³ and 100 kg/m³ (end-points included) and more particularly comprised between 85 kg/m³ and 91 kg/m³ (end-points included).

The mineral wool of the insulating component 7 is therefore more dense than that of the mineral wool of the insulating layer 5 and is in particular configured in the form of a rigid panel or of a strip.

The mineral wool of the insulating component 7 is created using high-temperature-resistance mineral fibers.

The applicant company markets a mineral wool suited to this application under the trade name “ULTIMATE”. For example, a product with reference U MPN 85 is suited to use according to the invention.

FIG. 3 shows, in a perspective view, a diagram of a reinforcing device 13 according to a first embodiment.

The reinforcing device 13 is, for example, made of metal, in particular bent sheet metal, preferably galvanized, and in cross section has the overall shape of a U, and the insulating component 7 is sandwiched between the reinforcing device 13 on the one hand, and the beam 3 on the other (see FIG. 2) or applied between the reinforcing device 13 and the facing (see FIG. 6).

More specifically, the reinforcing device 13 is formed of a frontal plate 15 and, for example, two pairs of legs 17A and 17B spaced apart in such a way as to be able to hold the beam 3 and, if appropriate, the insulating component 7, between said pairs of legs 17A and 17B.

Thus, the bottom of the U formed by the frontal plate 15 is positioned level with the frontal face 9 and the pairs of legs 17A, 17B of the U are level with the lateral faces 11, each pair of lateral legs 17A, 17B being fixed at the level of an end zone 19A, 19B in the lateral face 11 of the beam 3, for example using screws (see FIG. 2).

The length of each pair of legs 17A, 17B of the reinforcing device 13 is dependent on the particular geometry of the wooden element that is to be protected and is generally designed to extend over at least half the thickness of the wooden element. Thus, the end zone 19A, 19B is able to accept a screw 23 which is anchored into the wooden element in a position situated beyond the half-way point of the thickness of the beam, at a maximized distance with respect to the face liable to be exposed to fire. The length of the legs is greater than or equal to 40 mm, in particular comprised between 50 mm and 70 mm (end-points included) and is in particular 60 mm.

In order to encourage the degassing of the wood in the event of fire, the reinforcing device 13 may comprise degassing openings 21 on the frontal plate 15 and on the legs 17A and 17B. These holes also make it easier to fit the screws 23, because of the drilling carried out. They also contribute to reducing the thermal bridge generated by the presence of the metal reinforcing device.

The applicant company has conducted fire resistance tests on such a building element 1. During these tests, the building elements 1 were subjected to a fire with gas burners on the side of the plasterboard facing sheets 4. In addition, the beams 3 were subjected to a load corresponding to 30% of the rupture load at ambient temperature without fire. These tests demonstrated that the fire resistance, in terms of its stability aspect, improved enormously and the load rupture duration in the event of a fire could be increased between 25% and 30% in comparison with wooden beams of building elements of the prior art.

According to the analyses performed by the applicant company, the insulating component 7 on the frontal face significantly delays the charring of the beam 3 on this frontal face 9.

Whereas in building elements of the prior art, even when the spaces between the beams are filled with an insulating layer, the fire quite quickly penetrates the gap and attacks the lateral faces of the beam.

By contrast, according to the present invention, thanks to the protection of the lateral faces 11 of the beam 3, a weakening of the structure of the beam 3 is also significantly delayed given that the cross section of the beam 3 available for loadbearing decreases more slowly.

The fact that the reinforcing device 13 is anchored laterally in the beam 3 in a zone which is not subjected to charring or is subjected to charring later, for example at the ends of the pairs of legs 19A and 19B, offers a number of advantages:

The length of time for which the insulating component 7 holds onto the beam 3 is increased.

The reinforcing device 13 also acts as a reinforcer for the beam 3. Specifically, even if the frontal face 9 begins to char, the reinforcing device 13 is still held stably by its fixing by its end zones 19A and 19B of the pairs of legs 17A and 17B, especially since the lateral fixing is offset along the thickness of the beam away from the surface liable to be exposed to the fire; the effect of this is that the facing sheet 4 which is made of a non-flammable material can be held in place for longer.

The loadbearing capacity of the wooden framework under degraded conditions is thus increased, and it is thus possible to conceive of developing buildings with a smaller quantity of wood per storey (beams of smaller cross section), or with more storeys, the maximum number of storeys permitted when building with wood being limited at the present time.

Finally, it was found that the facing sheets 4 deform less and later when exposed to fire.

It will therefore be appreciated that the insulating component 7 makes a significant contribution to increasing the fire resistance of the wooden beams 3 of a building element 1 according to the invention.

FIG. 4 shows another embodiment of a reinforcing device 13. This differs from that of FIG. 3 through the shape of the pairs of legs 17A and 17B which are connected by a recessed central portion 17C.

This shape is suited to the manufacture of pairs of reinforcing devices 13 the lateral legs of which have complementary shapes of cutout.

This is shown in greater detail in FIG. 5. To manufacture the reinforcing device 13 according to FIG. 4, two symmetric and alternating wavy shapes 30 and 31 are cut out from a strip of sheet metal making it possible to obtain an alternation along a strip of sheet metal of a first component 33 in the overall shape of an H and a second component 35 in the overall shape of a diamond of rounded shape, truncated at the top and the bottom.

For each of the components 33 and 35 two fold lines 37 and 39 are defined in order to obtain on the one hand the frontal plate 15 and, on the other hand, the pairs of lateral legs 17A and 17B in the case of the component 33, and a pair of legs in the case of the component 35.

According to an alternative form that has not been depicted, provision is also made for the mineral wool insulating component 7 also to cover the rear face of the beam 3 which is the opposite face to the frontal face 9.

FIG. 6 shows a second embodiment of the building element 1 according to the invention.

This embodiment of FIG. 6 differs from that of figure in that the reinforcing device 13 is fixed directly to the wooden beam 13 and reinforces same. The reinforcing device 13 is therefore interposed between the insulating component 7 on the one hand and the wooden beam 3.

During the fire testing, it was found that the charring of the frontal face 9 could be delayed, thus also contributing to better fire resistance of the building element 1.

For all the embodiments, the insulating component 7 is fixed to the beam using screws and/or an adhesive and/or staples.

FIG. 7 shows a wooden beam 3 fitted with two complementary reinforcing devices 33 and 35.

The building elements 1 according to the invention can be marketed prefabricated but it is also possible to contemplate protection kits so that a building element 1 can be created on site. Such a kit comprises at least one panel or a strip of mineral wool corresponding to the insulating component 7 and a device 13 for reinforcing the panel on the frontal and lateral faces of a wooden beam.

In order to allow easy flat pack storage, a protection kit is provided that has at least three chamfered panels 71, 72 and 73 which are connected by their outer faces by pliable hinges 75 or film hinges, as shown in FIGS. 8 and 9.

Of course, it is also possible to provide three panels, which may or may not be chamfered, and which are connected in such a way as to form a U able to fit around a wooden beam.

Advantageously, the protection kit also comprises at least one reinforcing device 13.

It will therefore be appreciated that, by using high-performance and fire resistant thermal insulation as a protection, the fire resistance of a building element made with wooden beams can be significantly lengthened. 

1. A building element for a building comprising: a framework with at least one wooden beam and at least one facing sheet fixed to the beam of the framework; and an insulating component made of mineral wool affixed to the beam in such a way as to cover said beam on a frontal face and on at least a part of lateral faces, the insulating component affixed to the frontal face being interposed between the facing sheet and the beam.
 2. The building element as claimed in claim 1, wherein the insulating component made of mineral wool covers the lateral faces completely.
 3. The building element as claimed in claim 1, wherein the insulating component made of mineral wool is also affixed to a rear face of the beam that is the opposite face to the frontal face, so that the insulating component completely surrounds said beam.
 4. The building element as claimed in claim 3, wherein, on each face to which the insulating component is affixed, an orientation of fibers of the insulating component comprises a component parallel to the face
 5. The building element as claimed in claim 1, wherein a thickness of the insulating component is greater than or equal to 15 mm.
 6. The building element as claimed in claim 1, wherein a density of the insulating component made of mineral wool is greater than or equal to 30 kg/m³.
 7. The building element as claimed in claim 1, wherein the mineral wool of the insulating component is made with high-temperature-resistance mineral wool fibers.
 8. The building element as claimed in claim 1, wherein the insulating component is affixed to the wooden beam by bonding and/or mechanical fastening.
 9. The building element as claimed in claim 8, further comprising: a reinforcing device having at least one part of U-shaped overall cross section, a bottom of the U being positioned facing the frontal face and lateral legs of the U facing the lateral faces, each lateral leg being fixed at an end zone in the lateral face of the beam, the insulating component being interposed either between the reinforcing device and the beam or between the bottom of the U and the facing sheet.
 10. The building element as claimed in claim 9, wherein a length of each lateral leg of the reinforcing device is greater than half a thickness of the beam.
 11. The building element as claimed in claim 9, wherein the reinforcing device comprises degassing openings.
 12. A reinforcing device for the building element as claimed in claim 1, comprising: a frontal face to be fixed facing a frontal face of a beam; at least two lateral legs to be fixed to the lateral sides of the wooden beam.
 13. The reinforcing device as claimed in claim 12, wherein a length of each lateral leg of the reinforcing device is greater than 40 mm.
 14. The reinforcing device as claimed in claim 12, wherein the reinforcing device comprises degassing openings.
 15. An assembly of reinforcing devices, comprising: at least one pair of the reinforcing device as claimed in claim 12, the respective lateral legs of which have complementary cutout shapes.
 16. A protection kit for creating the building element as claimed in claim 1, comprising: at least one mineral wool panel; and means of reinforcing the panel on the frontal and lateral faces of a wooden beam.
 17. The protection kit as claimed in claim 16, further comprising: a panel formed of three continuous or contiguous segments connected by their external faces, the panel being configured to be folded along pliable hinges so that the panel surrounds the wooden beam.
 18. The building element as claimed in claim 1, wherein a thickness of the insulating component is between 15 mm and 50 mm.
 19. The building element as claimed in claim 1, wherein a density of the insulating component made of mineral wool is between 80 kg/m³ and 100 kg/m³.
 20. The building element as claimed in claim 3, wherein, on each face to which the insulating component is affixed, a dominant direction of an orientation of the mineral fibers of the insulating component made of mineral wool is parallel to the face. 